Evaluation of underwater noise from vessels and marine activities

Underwater noise and its impact on the environment has been an area of growing interest, particularly in the last decade. Concerns over noise produced by human operations at sea have restricted marine operations in environmentally sensitive areas such as the Beaufort Sea (North of Alaska), the Caspian Sea, and elsewhere around the world. The International Maritime Organization is now considering regulations on underwater noise for shipping, at a minimum, to combat the rise in noise levels in the world´s oceans. Such concerns and regulations point to the need for a measurement system that can evaluate underwater noise generation from marine activities. To assist in evaluating the underwater noise from vessels, the authors have recently developed such a measurement system that is also highly portable and easily deployed. The system was originally developed to perform testing that complies with new underwater noise measurement standards such as ANSI/ASA S12.64 and DNV SILENT Class. However, its capabilities can be extended to assess noise from a variety of marine sources including seismic exploration, explosives, construction, offshore platforms, and more. This paper presents an overview of the system design, its capabilities, as well as case studies where the system was deployed in the field to perform underwater noise measurements.